feat: add extensible mail flags

worker/src/admin_api/db_api.ts

@@ -11,6 +11,7 @@ CREATE TABLE IF NOT EXISTS raw_mails (
     raw TEXT,
     raw_blob BLOB,
     metadata TEXT,
+    flags INTEGER NOT NULL DEFAULT 0,
     created_at DATETIME DEFAULT CURRENT_TIMESTAMP
 );
 
@@ -197,6 +198,17 @@ export default {
                 await c.env.DB.exec(`ALTER TABLE raw_mails ADD COLUMN raw_blob BLOB;`);
             }
         }
+        if (version && version <= "v0.0.7") {
+            const tableInfo = await c.env.DB.prepare(
+                `PRAGMA table_info(raw_mails)`
+            ).all();
+            const hasFlags = tableInfo.results?.some(
+                (col: any) => col.name === 'flags'
+            );
+            if (!hasFlags) {
+                await c.env.DB.exec(`ALTER TABLE raw_mails ADD COLUMN flags INTEGER;`);
+            }
+        }
         if (version != CONSTANTS.DB_VERSION) {
             // remove all \r and \n characters from the query string
             // split by ; and join with a ;\n